ENVISAT - AATSR CYCLIC REPORT #63

Transcription

1 ENVISAT - AATSR CYCLIC REPORT #63 START END DATE 29 OCT DEC 2007 TIME 21:59:29 21:59:29 ORBIT # Himalayas, 18 November 2007 Daytime visible image showing snow on the Western Himalayas. AATSR DPQC and QWG team November 2007 Technical Note

2 AATSR Cyclic Report Cycle 63 A P P R O V A L 1 0 Gordon Mack/Siân Procter 17 December 2007 C H A N G E L O G 0 C H A N G E R E C O R D! "! "

3 T A B L E O F C O N T E N T S AATSR CYCLIC REPORT # INTRODUCTION Acronyms and Abbreviations SUMMARY SOFTWARE & AUX FILE VERSION CONFIGURATION Software Version Auxiliary Files Status of Daily Visibile Calibration Files VC1 File Availability Status of other Auxiliary Files PDS STATUS Instrument Unavailability L0 Data Acquisition and L1b Processing Status Orbits Affected by Poor Data Quality L0 and L1b Backlog Processing Status DATA QUALITY CONTROL Monitoring of Instrument Parameters Jitter Sensor Temperature Viscal NET User Rejections Software Problem Reporting Existing SPRs that are still open New SPRs since the last cyclic report Closed SPRs CALIBRATION/VALIDATION ACTIVITIES & RESULTS Calibration Validation DISCLAIMERS...13

4 AATSR CYCLIC REPORT # 63 1 INTRODUCTION The AATSR Cyclic Report is distributed by the AATSR DPQC team to keep the AATSR community informed of any modification regarding instrument performances, the data production chain and the results of calibration and validation campaigns at the end of each Envisat cycle, which consists of 501 complete orbits over the course of 35 days. This document is available online at: Acronyms and Abbreviations AATSR Advanced Along Track Scanning Radiometer APC Antenna Pointing Controller CR Cyclic Report DDS Data Dissemination System DMOP Detailed Mission Operation Plan DMS Data Management System DPQC Data Product Quality Control EN-UNA-YYYY/# Envisat Unavailability (plus year and number) ESOC European Space Operation Centre HSM High Speed Multiplexer IECF Instrument Engineering and Calibration Facilities IPF Instrument Processing Facilities LUT Look Up Table MPS Mission Planning Schedule NRT Near Real Time OCM Orbit Control Manoeuvre OBDH On-board Data Handling PDS Payload Data Segment PMC Payload Management Computer SPR Software Problem Reporting SW Software VISCAL Visible Calibration!

5 2 SUMMARY Cyclic Report: 63 Cycle Start: 29 Oct 2007, 21:59:29 Orbit #: Cycle End: 03 Dec 2007, 21:59:29 Orbit #: The main activities during the cycle have been as follows: L0 Processor and IPF Version: L0 Processor no change (5.22) Level 1b & Level 2 processor no change (6.01) Visible channel calibration: The visible calibration data supplied as an aux file (ATS_VC1_AX) continued to be regularly updated throughout the cycle. Blackbody Crossover Test: An AATSR blackbody crossover test was initiated on 13 th November :50 and was completed on 15 th November :40. Scientific data for orbits will not be optimally calibrated as a result.

6 # # 3 SOFTWARE & AUX FILE VERSION CONFIGURATION 3.1 Software Version AATSR IPF for Level 1 and Level 2: Version Auxiliary Files AATSR processing uses the following auxiliary files: Browse Product Lookup Data L1b Characterisation Data Cloud Lookup Table Data General Calibration Data AATSR Instrument Data Visible Calibration Coefficients Data L1b Processing Configuration Data L2 Processing Configuration Data SST Retrieval Coefficients Data LST Land Surface Temperature Coefficients Data (ATS_BRW_AX) (ATS_CH1_AX) (ATS_CL1_AX) (ATS_GC1_AX) (ATS_INS_AX) (ATS_VC1_AX) (ATS_PC1_AX) (ATS_PC2_AX) (ATS_SST_AX) (ATS_LST_AX) The latest filename for each auxiliary file in use in the PDS is as follows: Product name ATS_BRW_AXVIEC _072338_ _000000_ _ ATS_CH1_AXVIEC _113144_ _000000_ _ ATS_CL1_AXNIEC _102348_ _120446_ _ ATS_GC1_AXVIEC _154941_ _000000_ _ ATS_INS_AXVIEC _092706_ _000000_ _ See below for VC1 files ATS_LST_AXVIEC _095537_ _000001_ _ ATS_PC1_AXVIEC _063722_ _000000_ _ ATS_PC2_AXVIEC _074151_ _000000_ _ ATS_SST_AXVIEC _102103_ _000000_ _ Table 3-1 Latest auxiliary files currently in use by the PDS

7 3.2.1 STATUS OF DAILY VISIBILE CALIBRATION FILES VC1 File Availability $ $ The daily reflectance channel calibration files were available for all dates, except for the following: 10 th November 2007 The orbital reflectance channel calibration files VC1 files were created from the available L0 files for all dates during this cycle STATUS OF OTHER AUXILIARY FILES No other auxiliary files changed during this cycle.

8 % % 4 PDS STATUS 4.1 Instrument Unavailability AATSR operations continued nominally throughout the reporting period. 4.2 L0 Data Acquisition and L1b Processing Status Week Orbit Availability (s) Availability (%) # Dates Start Stop Inst Unav L0 gaps L1 gaps Instrument L0 L1 1 October 29, % 98.97% 98.97% 2 November 5, % % % 3 November 12, % 99.01% 99.01% 4 November 19, % % % 5 November 26, % 99.05% 99.05% Table 4-1 Instrument and data unavailability weekly summary for cycle 63 The instrument was available for % of the time during the cycle. The L0 data were available for 99.41% of the time during the cycle. The L1b data were available for 99.41% of the time during the cycle. The following L0 data was missing from this cycle: NB Missing L0 data are automatically also missing at L1b; there were no additional missing L1b data during this cycle. UTC Start UTC Stop Duration (s) Orbit Start Orbit End 29-Oct :23 29-Oct : Oct :25 30-Oct : Nov :59 19-Nov : Nov :59 28-Nov : Oct :23 29-Oct : Table 4-2 ATS_NL 0P missing data during cycle ORBITS AFFECTED BY POOR DATA QUALITY The information reported in Section 4.2 does not consider the quality of data, only whether or not it is available. During this cycle, the following orbits contained frames suffering from bad/missing telemetry: (13 th November 2007) (13 th November 2007) (14 th November 2007)

9 & & (14 th November 2007) (18 th November 2007) (28 th November 2007) (2 nd December 2007) (3 rd December 2007) 4.3 L0 and L1b Backlog Processing Status The following data, reported missing from previous cycles, have been retrieved via backlog processing: UTC Start UTC Stop Orbit Start Orbit End Duration (s) 24-Sep :23 24-Sep : Sep :27 24-Sep : Sep :52 24-Sep : Table 4-3 Backlog processing status during cycle 63

10 5 DATA QUALITY CONTROL 5.1 Monitoring of Instrument Parameters JITTER Figure 5-1 Jitter trend from mission start The plot shows the jitter-trend since the start of the mission, against both orbit-number and cycle-number. The mean jitter-rate (per-orbit) is shown in blue and the maximum rate per orbit in red. The green horizontal line shows the nominal mean jitter-level achieved for much of the mission. The jitter plot shows some marginal improvement with respect to the previous cycle in both the mean and maximum jitter-rate. There is no significant deterioration in image quality associated with these jitter levels, but this is continually monitored SENSOR TEMPERATURE While in measurement mode, all sensors maintained their nominal orbital and seasonal ranges in this cycle VISCAL Reflectance channel calibration files are available for most days in these cycles, except: November 10 In addition, the following set of orbit-by-orbit VC1 files was delivered:

11 5.1.4 NET ' ' Hot BB Cold BB T = K T = K Count NE T (mk) Count NE T (mk) 12µm µm µm Table 5-1 NE T data for Cycle 63 Hot BB Cold BB T = K T = K Count NE T (mk) Count NE T (mk) 12µm µm µm Table 5-2 NE T data for Cycle 62 Hot BB Cold BB T = K T = K Count NE T (mk) Count NE T (mk) 12µm µm µm Table 5-3 NE T data for Cycle User Rejections There were no user rejections during this cycle. 5.3 Software Problem Reporting This section describes the open SPRs, their potential impact on the data quality, and SPRs that have been closed EXISTING SPRS THAT ARE STILL OPEN The following SPRs are still open: Inconsistent values in AST Confidence word, 17 and 50km cells NA-PR The AST confidence word may be incorrectly set for records where the nadir or dual view SST retrieval was invalid, indicating that the 3.7 micron channel was used (although this has no meaning in this instance). Although the wrongly set flags may be ignored as far as the 17km cell is concerned, they present a problem since they may propagate into the confidence word for the 50km cell. The problem does not occur for daytime (descending) arcs where the retrievals are valid for both views.

12 5.3.2 NEW SPRS SINCE THE LAST CYCLIC REPORT No SPRs have been opened since the last Cyclic Report CLOSED SPRS No SPRs have been closed since the last Cyclic Report. ( (

13 6 CALIBRATION/VALIDATION ACTIVITIES & RESULTS 6.1 Calibration No additional calibration results were reported during this cycle. 6.2 Validation A monthly mean global dual-view SST plot for Cycle 63 composed from ATS_AR 2P 10' data is shown below in Figure 6-1. The monthly mean contains day time and night time data. Figure 6-1: Monthly Global Average dual-view SST for Cycle 63. The Met Office has validated the AATSR dual-view SST data using the global network of in situ buoy SST data, the results for Cycle 63 being shown in Figure 6-2. The updated SST coefficients released in December 2005 were used in the AATSR SST retrievals.

14 Figure 6-2: Comparison of daily mean difference between 10 AATSR SST values and in situ buoy SST for Cycle 63. Data provided by the Met Office. During cycle 63, there were 1886 night time match-ups, with a mean (UL derived dualview skin SST minus buoy SST) of K, standard deviation 0.26 K, and a mean (dualview bulk SST minus buoy SST) of K, standard deviation 0.25 K. A total of 1746 daytime match-ups were found, with a mean (UL derived dual-view skin SST minus buoy SST) of K, standard deviation 0.33 K, and a mean (dual-view bulk SST minus buoy SST) of K, standard deviation 0.33 K. As these data are comparisons of a single point buoy measurement against a much larger spatially averaged value they are not a true indicator of AATSR s accuracy and are used to show consistency of data quality between cycles. Figure 6-3: Plot of daily number of match-ups between 10 AATSR SST values and in situ buoy SST for Cycle 63. Data provided by the Met Office.

15 Figure 6-4: Map showing global distribution of match-ups between 10 AATSR SST values and in situ buoy SST for Cycle 63. The red dots indicate a match-ups to a moored buoy; the cyan dots indicate a match-up to a drifting buoy. Data provided by the Met Office. A complete update on the status of the instrument validation can be found in Section of Cyclic Report 28.

16 # # 7 DISCLAIMERS No new disclaimers have been issued during this cycle.